Primary hypothesis In a group of high risk hypertensive patients for the same level of blood pressure control the angiotensin II receptor antagonist valsartan will be more efficacious in reducing acute myocardial infraction, congestive heart failure and cardiac mortality than the calcium channel blocker amlodipine. Secondary hypothesis For the same level of BP control valsartan will be more efficacious than the calcium channel blocker amlodipine in reducing all causes of death, cerebrovascular morbidity/mortality, and coronary events other than acute myocardial infarction/mortality. The objective is to execute a study capable of detecting a 15% difference in cardiovascular morbidity and mortality between a group of hypertensive patients treated with valsartan 80 and 160 mg, with or without the addition of hydrochlorathiazide once daily compared to a group treated with amlodipine 5 and 10 mg once daily, with or without addition of hydrochlorothiazide.